Body Mass Index
The body mass index (BMI) assesses body weight relative to height. You can calculate your BMI by taking your weight in kilograms and dividing it by your height in metres squared (BMI = kg/m2) or your weight in pounds divided by the square of your height in inches and multiplying that number by 704.5 (BMI = lb/in2 x 704.5).
If you find the math challenging, you can check your BMI on a standard BMI table found in many pharmacies and medical offices. If you have access to the Internet, there are many interactive BMI calculators that will do the math for you after you enter your height and weight.
Several sites that offer this service include:
- http://www.hc-sc.gc.ca/hpfb-dgpsa/ onpp-bppn/bmi_chart_java_e.html
- http://nhlbisupport.com/bmi/bminojs.htm
- http://www.cdc.gov/nccdphp/dnpa/bmi/calc-bmi.htm
Once you know your BMI, you can use it to help determine how healthy your weight is in relation to your height.
- BMI below 18.5 is considered underweight.
- BMI between 18.5 and 24.9 is considered the normal, healthy range.
- BMI between 25 and 29.9 is considered overweight.
- BMI over 30 is considered obese.
It is important to remember that the BMI is only one indicator of a healthy weight. It has limitations and does not apply to children, pregnant women, or people with very muscular bodies. If your BMI falls outside the healthy range, ask your doctor to assess your weight to see if it is in the healthy range for you.
Hip-to-Waist Ratio
There’s a quick and easy method to determine your risk of cardiovascular disease based upon where your body stores its excess fat. Because there is a higher risk associated with fat stored around the abdomen (the “apple-shaped” body) than there is from fat stored in the hip area (the “pear-shaped” body), the hip-to-waist ratio (HWR) can be a useful tool. To calculate your HWR, measure your waist at the smallest part, generally a few centimetres above your navel. Then measure your hips at the widest point, including your buttocks. Now divide your waist measurement by your hip measurement to determine your hip-to-waist ratio.
Women with a HWR greater than 0.8 and men with a HWR greater than 1.0 have a higher risk of developing heart disease and type 2 diabetes and should try to reduce their abdominal body fat.
Achieving a Healthy Weight
If you discover that your weight is not in the healthy range, you should talk to your doctor about ways to bring it in line. We all know that being overweight can have serious health consequences, but many people don’t realize that being underweight can also cause health problems. Your doctor can help you work out a plan of nutritious eating that will address your particular set of circumstances.
To assist Canadians in developing nutritious meal plans that encourage healthy eating habits, Health Canada has developed Canada’s Food Guide to Healthy Eating— commonly referred to as the Food Rainbow—which outlines the four main food groups and explains which foods fall into which group and how many servings we should choose from each group every day.
Health Canada has also established a set of guidelines for healthy eating that are based on these five principles:
- Enjoy a variety of foods.
- Emphasize cereals, breads, other grain products, vegetables, and fruits.
- Choose lower-fat dairy products, leaner meats, and foods prepared with little or no fat.
- Achieve and maintain a healthy body weight by enjoying regular physical activity and healthy eating.
- Limit salt, alcohol, and caffeine.
One of the keys to achieving and maintaining a healthy weight is portion control. Some studies have shown that people often underestimate the number of calories they consume daily by as much as 25%.
To help you determine what an appropriate portion size is, Health Canada has developed a list of sample sizes for a single serving of foods from the four food groups.
- Grain products: 1 slice of bread; 1/2 bagel, bun, or pita; 175 mL (3/4 cup) of hot cereal; 30 g (1 oz.) of cold cereal; 250 mL (1 c.) cooked pasta; or 250 mL (1 c.) cooked rice.
- Vegetables & fruits: 1 medium-sized fresh vegetable or fruit; 125 mL (1/2 c.) fresh, frozen, or canned vegetable or fruit; 250 mL (1 c.) salad; or 125 mL (1/2 c.) juice.
- Milk products: 250 mL (1 c.) milk; 175 g (3/4 c.) yogurt; 50 g (2 slices or a chunk measuring 3” x 1” x 1”) cheese.
- Meat & alternatives: 50 – 100 g (11/2–3 oz.) meat, poultry, or fish; 1 – 2 eggs; 100 g (1/3 c.) tofu; 125 – 250 mL (1/2– 1 c.) beans; or 30 mL (2 tbsp.) peanut butter.
It isn’t always possible to measure or weigh foods before we eat them, especially when dining out. The following list provides a more practical way of estimating the size of a portion of some common foods.
- Vegetables & fruit: about the size of your fist
- Pasta or rice: about the size of one scoop of ice cream
- Meat, fish, or poultry: about the size of a deck of cards or the size of your palm (without the fingers)
- Cheese: about the size of a pair of dice or the size of your thumb from the tip to the base
Although dieting alone can help you lose weight, adding exercise into your daily schedule can speed up the process. The goal of exercise in a weight loss program is to help burn more calories.
One of the best ways to lose body fat is through steady aerobic exercise (such as walking) for at least 30 minutes most days of the week. Strength training exercises, like weight lifting, can also help counteract the muscle loss associated with aging. And since muscle tissue burns more calories, muscle mass is a key factor in maintaining a healthy weight.
Exercise sensibly by starting slowly and gradually increasing the duration and intensity of your workout. Even though regularly scheduled aerobic exercise is the best way to lose fat, any extra movement burns calories. Stair climbing, gardening, lawn mowing, and housework all help you lose weight.
And exercise itself, apart from its role in weight loss, has many health benefits—even for people whose weight is in the healthy range. But before you start any exercise program, check with your doctor to make sure that the activity you are planning is appropriate in terms of your age, overall health, and state of physical fitness.
What about diet aids?
Most diet pills, liquid diets, and “diet teas” are short-term solutions that won’t work without long-term changes in your eating habits and physical activity level. Many of these products contain mild stimulants or diuretics that cause you to eliminate fluids faster than usual. And they can produce side effects, especially for people with certain health conditions, so you should always check with your doctor or pharmacist before deciding to use one of these products.
Sometimes people turn to supplements that claim to aid weight loss. Some of these can be dangerous; others are ineffective. It pays to analyze these claims carefully. If there were a simple solution to weight loss, no one would be overweight. If you want to try one of these products, be sure to check with your doctor or pharmacist first to make sure that it will not have a negative impact on any health condition you may have or will interact with any other medicine you are taking.
Fad diets can be another no-lose/no-win situation. Most of these diets gain quick popularity due to media coverage; then they fade quickly, only to be replaced by the next fad. The problem is that many of these diets are based on an eating plan that is not nutritionally balanced; some even eliminate an entire food group. This can cause health problems, and the weight lost is usually regained quickly once the diet regimen is stopped.
There is one simple rule governing weight loss: you must use up more calories (energy) than you take in.
If you are obese, your doctor may consider putting you on a medically supervised weight loss plan. Losing even 5% to 10% of your body weight can improve blood pressure, cholesterol, and blood sugar levels. In some cases, a doctor may prescribe a prescription medication to help curb your appetite or to keep your body from absorbing all of the fat in the food you eat. However, these medications can have significant side effects, so they must be taken exactly as prescribed.
Achieving and maintaining a healthy weight will help you feel great, look good, and help prevent many health conditions that are associated with being overweight.
If you have any questions about weight management, speak to your doctor or pharmacist.
